OBJECTIVES: 1. To search for the location of the enzyme or enzyme systems which metabolize B(a)P into 6-hydroxybenzo(a)pyrene and related quinones. For instance, we would like to know whether that enzyme system is located in the nucleus or in the microsome. 2. To isolate and to study the chemical reaction product between nucleic acid and polynucleotides with a 6-hydroxybenzo(a)pyrene and the 6-oxo-benzo(a)pyrene radical. 3. To study various factors, including inhibitors and inducers on the metabolism of benzo(a)pyrene to 6-hydroxybenzo(a)pyrene and the related quinones. 4. To investigate the properties of spin label in nucleic acid and to build up a library of ESR spectra of the spin label linked to nucleic acid when the nucleic acid exists in a variety of conformations and structures.